In the manufacture of cloth products, such as napkins and washcloths that include folded hems, the products are usually manufactured by cutting a long length of cloth in smaller sections, and a sewing machine operator folds the edges over to form hems and sews around the four sides of the product. This prevents the hem from raveling and forms an attractive edge on the product.
Although many attempts have been made in an effort to automatically form hems in cloth lengths, only a few attempts have been considered commercially successful, and most of the attempts have failed where relatively small hems are to be formed in relatively bulky materials, such as the typically small hems in washcloths, towels and other objects fabricated from similar materials. As the hems get smaller and the thickness of the material increases, it is more difficult to automatically form the hem.
As illustrated in U.S. Pat. Nos. 3,640,235, 3,773,002, 3,722,435 and 3,580,198, various attempts have been made to automatically hem the edges of cloth sections. For example, U.S. Pat. No. 3,580,198 discloses a system which hems the opposite edges of a continuous length of cloth, cuts the length into sections, turns the length 90.degree. as it continues to move in its rectilinear path, and then hems the opposite cut edges of the sections. U.S. Pat. Nos. 3,640,235 and 3,772,948 disclose systems which cut cloth sections from a continuous length of cloth, moves the cut lengths at a right angle with the cut edges parallel to the path of movement, hems one cut edge, and then flips the other cut edge over so that it can be hemmed by another "right-handed" sewing machine. U.S. Pat. No. 3,722,435 also discloses a right angle system but which utilizes a turning drum and conveyor tapes for turning the cloth sections over so that "right-handed" sewing machines can be used to hem the opposite cut edges of the cloth sections.
In addition to the cloth handling and guidance systems described in the preceding patents, various attempts have been made to control the movement of a folded hem and the body of a cloth section as the edge portion of the cloth section is folded over and sewn closed. For example, U.S. Pat. No. 3,906,878 discloses a system in which a double fold is formed in the edge portion of a cloth section and the velocity of the folded portion as it approaches the sewing machine is controlled so as to prevent a "dog ear" or "hangout" from occurring in the hem of the cloth section.